Issue seems to be fixed with Windows 10 19H1 Insider Preview Build 18361 ! Quoting from Microsoft's Changelog: "We fixed an issue preventing certain VMs from being able to install or update Windows Insider Preview builds ..."
Seems this was no qemu issue after all, please close. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1819649 Title: Win10 Preview Build 18351 - no input Status in QEMU: New Bug description: The issue exists in both 2.12.1 and current master (built 8.3.2019). Neither keyboard nor mouse input seems to work and there's no cursor available (VNC, SPICE, SDL tested). If all the 'hv_*' flags are removed input works again. In the attachments you can find a simple script to reproduce it (requires the ISO path to be changed). To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1819649/+subscriptions